[TowerTalk] Antenna loads for rohn 45

[Jim Thomson]

Date: Sat, 17 Jul 2010 18:39:47 -0400
From: <john at kk9a.com>
Subject: Re: [TowerTalk] Antenna loads for rohn 45


 I doubt solid legs would change the load rating much, but they would be 
very nice for towers installed in corrosive locations.  Does Rohn really 
make a solid leg 45g tower?

John P40A

##  PI-rod uses solid legs.. as do several other tower makers.. both in Na  and in EU. 
Trylon  makes  an 18"  tower, with 7/8"  solid legs that they rate higher than 65-G . 135 lbs per section,
and the bracing is 1/2"  instead of the usual 7/16".   Hollow tube is welded to the sides  of the bottom
 and top of each tower section.   A  6.5" bolt  [5/8''] is dropped into the mating hollow tubes to splice the
 sections together.  [ 3 x bolts  per splice, one per each leg]    All u need is to drop just one bolt in.. and
 swing the tower around.. till the other 2 x legs line up, then drop the 2 x remaining bolts into place.  They
come apart real easy.  

##  I just saw pix of old 25/45 G... bottom section in each case... where the legs were just abt rusted out
from the inside !   A real mess.   Most of that comes from the legs filling up with water/condensation... and
then not being able to drain out the bottom.   Even with a layer of gravel below the concrete, it's still dicey. 

With solid legs, you can just stuff the bottom section right into the concrete, or use a base plate /pier pin set up ,etc.

I saw one free standing tower back in the 80's, that used big diam hollow legs, that used pipe legs and not tubing.
The standing water inside the legs froze.. and split the seam  wide open in one of the 3 x legs !   The 3 x seams
were all pointing at the center of the 30" wide tower.     The split seam was from 4" above the cement to abt 17"
above the cement.  And that tower had square flange plates welded to the bottoms of each leg.. like  65-G. 
Just above the welded square plate, was a  drain hole.. which obviously must have gotten plugged.   That 
could have easily happened on a upper section as well, since all the sections used square plates. 

Solid legs are an excellent idea imo.  Angle steel legs are good too, water wise.   Solid legs provide the least
wind resistance.  Angle legs are max wind resistance.. and ditto with angle bracing. 

later... Jim   VE7RF